Endocrinology Exam Questions

Correct Answer: A

Rationale: Phaeochromocytoma is a rare neuroendocrine tumor that usually originates from the adrenal glands and produces excess catecholamines. The characteristic symptoms of phaeochromocytoma include paroxysmal (sudden and severe) hypertension, fear of impending death (angor animi), and episodic symptoms like palpitations, headache, and diaphoresis. However, weight gain is not a typical manifestation associated with phaeochromocytoma. In fact, patients with this condition may experience unintentional weight loss due to the effects of excess catecholamines on metabolism and appetite suppression. Therefore, weight gain is not a significant feature observed in individuals with phaeochromocytoma.

Correct Answer: A

Rationale: Phaeochromocytoma is a rare neuroendocrine tumor that usually originates from the adrenal glands and produces excess catecholamines. The characteristic symptoms of phaeochromocytoma include paroxysmal (sudden and severe) hypertension, fear of impending death (angor animi), and episodic symptoms like palpitations, headache, and diaphoresis. However, weight gain is not a typical manifestation associated with phaeochromocytoma. In fact, patients with this condition may experience unintentional weight loss due to the effects of excess catecholamines on metabolism and appetite suppression. Therefore, weight gain is not a significant feature observed in individuals with phaeochromocytoma.

Correct Answer: C

Rationale: Hypercalcemia refers to elevated levels of calcium in the blood. The effects of hypercalcemia include increased urinary frequency (polyuria), gastrointestinal symptoms such as constipation rather than diarrhea, kidney stones (nephrolithiasis), and various cardiac abnormalities. One key cardiac abnormality associated with hypercalcemia is a prolonged QT interval rather than a shortened QT interval. Prolongation of the QT interval can predispose individuals to arrhythmias, particularly Torsades de pointes. Therefore, the correct answer is C, as a shortened QT interval is not a typical effect of hypercalcemia.

Correct Answer: A

Rationale: Oxytocin is a hormone produced by the hypothalamus and released by the pituitary gland. In the bloodstream, oxytocin is mostly bound to a carrier protein called neurophysin. This binding helps to protect oxytocin from being degraded too quickly in the bloodstream, thus allowing it to exert its effects on target tissues such as the uterus and mammary glands. Oxytocin plays important roles in stimulating uterine contractions during labor, facilitating milk letdown during breastfeeding, and promoting social bonding and emotional connections.

Correct Answer: B

Rationale: Small cell (oat cell) carcinoma of the lung is most commonly associated with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). This paraneoplastic syndrome occurs in patients with small cell lung cancer due to the production of antidiuretic hormone (ADH) by the tumor cells. The excessive release of ADH leads to water retention and dilutional hyponatremia, causing symptoms such as nausea, confusion, seizures, and potentially life-threatening complications. Other types of lung cancer, such as squamous cell carcinoma, large cell carcinoma, and adenocarcinoma, are less commonly associated with SIADH.